Even as technology progresses at a blinding speed, the skilled examiner remains the most valuable segment of the medical repertoire in determining gestational age of a newborn.
| Year | Author | Subject |
| 1920 | Steeter | Foot lengths of human embryos |
| 1955 | St. Anne Dargassie | Neurologic maturation in premature infants |
| 1964 | Dotson | Muscle tone in term infants |
| 1966 | Farr, Usher | External characteristics in assessing gestation |
| 1971 | Dubowitz | A scoring system for assessing gestation |
| 1979 | Ballard | A simplified score applicable to sick babies |
| 1980 | Pearson | Development of the human eyelids |
| 1984 | Hern | Foot lengths confirmed |
| 1986 | Amiel Tison | Tone: Active and passive Primitive reflexes in assessing gestation |